Buggy code:
public class Snippet210 { static String string = "A<seq2seq4repair_space>drag<seq2seq4repair_space>source<seq2seq4repair_space>is<seq2seq4repair_space>the<seq2seq4repair_space>provider<seq2seq4repair_space>of<seq2seq4repair_space>data<seq2seq4repair_space>in<seq2seq4repair_space>a<seq2seq4repair_space>Drag<seq2seq4repair_space>and<seq2seq4repair_space>Drop<seq2seq4repair_space>data<seq2seq4repair_space>transfer<seq2seq4repair_space>as<seq2seq4repair_space>well<seq2seq4repair_space>as<seq2seq4repair_space>" + ( ( ( ( "the<seq2seq4repair_space>originator<seq2seq4repair_space>of<seq2seq4repair_space>the<seq2seq4repair_space>Drag<seq2seq4repair_space>and<seq2seq4repair_space>Drop<seq2seq4repair_space>operation.<seq2seq4repair_space>The<seq2seq4repair_space>data<seq2seq4repair_space>provided<seq2seq4repair_space>by<seq2seq4repair_space>the<seq2seq4repair_space>drag<seq2seq4repair_space>source<seq2seq4repair_space>" + "may<seq2seq4repair_space>be<seq2seq4repair_space>transferred<seq2seq4repair_space>to<seq2seq4repair_space>another<seq2seq4repair_space>location<seq2seq4repair_space>in<seq2seq4repair_space>the<seq2seq4repair_space>same<seq2seq4repair_space>widget,<seq2seq4repair_space>to<seq2seq4repair_space>a<seq2seq4repair_space>different<seq2seq4repair_space>widget<seq2seq4repair_space>" ) + "within<seq2seq4repair_space>the<seq2seq4repair_space>same<seq2seq4repair_space>application,<seq2seq4repair_space>or<seq2seq4repair_space>to<seq2seq4repair_space>a<seq2seq4repair_space>different<seq2seq4repair_space>application<seq2seq4repair_space>altogether.<seq2seq4repair_space>For<seq2seq4repair_space>example,<seq2seq4repair_space>" ) + "you<seq2seq4repair_space>can<seq2seq4repair_space>drag<seq2seq4repair_space>text<seq2seq4repair_space>from<seq2seq4repair_space>your<seq2seq4repair_space>application<seq2seq4repair_space>and<seq2seq4repair_space>drop<seq2seq4repair_space>it<seq2seq4repair_space>on<seq2seq4repair_space>an<seq2seq4repair_space>email<seq2seq4repair_space>application,<seq2seq4repair_space>or<seq2seq4repair_space>you<seq2seq4repair_space>" ) + "could<seq2seq4repair_space>drag<seq2seq4repair_space>an<seq2seq4repair_space>item<seq2seq4repair_space>in<seq2seq4repair_space>a<seq2seq4repair_space>tree<seq2seq4repair_space>and<seq2seq4repair_space>drop<seq2seq4repair_space>it<seq2seq4repair_space>below<seq2seq4repair_space>a<seq2seq4repair_space>different<seq2seq4repair_space>node<seq2seq4repair_space>in<seq2seq4repair_space>the<seq2seq4repair_space>same<seq2seq4repair_space>tree." ) ; public static void main ( String [ ] args ) { final Display display = new Display ( ) ; Shell shell = new Shell ( display ) ; shell . setLayout ( new FillLayout ( ) ) ; int style = ( ( ( ( SWT . MULTI ) | ( SWT . WRAP ) ) | ( SWT . H_SCROLL ) ) | ( SWT . V_SCROLL ) ) | ( SWT . BORDER ) ; final StyledText text = new StyledText ( shell , style ) ; text . setText ( Snippet210 . string ) ; DragSource source = new DragSource ( text , ( ( DND . DROP_COPY ) | ( DND . DROP_MOVE ) ) ) ; source . setTransfer ( new Transfer [ ] { TextTransfer . getInstance ( ) } ) ; source . addDragListener ( new DragSourceAdapter ( ) { public void dragStart ( DragSourceEvent e ) { Point selection = text . getSelection ( ) ; int offset = text . getOffsetAtLocation ( new Point ( e . x , e . y ) ) ; e . doit = ( offset > ( selection . x ) ) && ( offset < ( selection . y ) ) ; } public void dragSetData ( DragSourceEvent e ) { Point selection = text . getSelection ( ) ; if ( ( selection . x ) != ( selection . y ) ) { <START_BUG> e . data = text . getText ( selection . x , selection . y ) ; <END_BUG> } } public void dragFinished ( DragSourceEvent e ) { if ( ( e . detail ) == ( DND . DROP_MOVE ) ) { text . insert ( "" ) ; } } } ) ; final Label label = new Label ( shell , ( ( SWT . BORDER ) | ( SWT . WRAP ) ) ) ; label . setText ( "Drop<seq2seq4repair_space>Target" ) ; DropTarget target = new DropTarget ( label , ( ( ( ( DND . DROP_DEFAULT ) | ( DND . DROP_MOVE ) ) | ( DND . DROP_COPY ) ) | ( DND . DROP_LINK ) ) ) ; target . setTransfer ( new Transfer [ ] { TextTransfer . getInstance ( ) } ) ; target . addDropListener ( new DropTargetAdapter ( ) { public void dragEnter ( DropTargetEvent event ) { if ( ( event . detail ) == ( DND . DROP_DEFAULT ) ) event . detail = DND . DROP_COPY ; } public void dragOperationChanged ( DropTargetEvent event ) { if ( ( event . detail ) == ( DND . DROP_DEFAULT ) ) event . detail = DND . DROP_COPY ; } public void drop ( DropTargetEvent event ) { label . setText ( ( ( String ) ( event . data ) ) ) ; } } ) ; shell . open ( ) ; while ( ! ( shell . isDisposed ( ) ) ) { if ( ! ( display . readAndDispatch ( ) ) ) display . sleep ( ) ; } display . dispose ( ) ; } }

Fix:
e . data = text . getText ( selection . x , ( ( selection . y ) - 1 ) ) ;